While installing or upgrading packages some of them gives hints with optional dependencies. Pacman should check if those dependecies are already installed and should not show them. = Just show uninstalled dependencies.


example:

pacman -S cups-filters
Optional dependencies for cups-filters:
ghostscript: for non-PostScript printers to print with CUPS to convert PostScript to raster images
foomatic-db: drivers use Ghostscript to convert PostScript to a printable form directly
foomatic-db-engine: drivers use Ghostscript to convert PostScript to a printable form directly
foomatic-db-nonfree: drivers use Ghostscript to convert PostScript to a printable form directly

It could be like this:
pacman -S cups-filters
Optional dependencies for cups-filters:
foomatic-db-nonfree: drivers use Ghostscript to convert PostScript to a printable form directly

Because other are already installed.

OR

pacman -S cups-filters
Optional dependencies for cups-filters:
ghostscript: for non-PostScript printers to print with CUPS to convert PostScript to raster images [INSTALLED]
foomatic-db: drivers use Ghostscript to convert PostScript to a printable form directly [INSTALLED]
foomatic-db-engine: drivers use Ghostscript to convert PostScript to a printable form directly [INSTALLED]
foomatic-db-nonfree: drivers use Ghostscript to convert PostScript to a printable form directly